MBSFN Subframe Configuration for eICIC Interference Coordination

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Solution Overview

Problem

Conventional LTE schemes lack a defined method for changing the setting of Almost Blank Subframes (ABS) and Multicast Broadcast Single Frequency Network (MBSFN) subframes, particularly when transitioning between those used for Enhanced Inter Cell Interference Coordination (eICIC) and those not used for eICIC.

Innovation Solution

A mobile communication method and radio base station configuration that allows for the appropriate adjustment of MBSFN subframes not used for eICIC and ABS/MBSFN subframes used for eICIC, by using setting units to determine and notify the patterns of these subframes through X2 eNB Configuration Updates, enabling temporal overlap and exclusion of MBMS data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the conventional LTE scheme uses MBSFN subframes for both eICIC and normal MBMS functions, then resource utilization is improved, but the ability to independently control and change settings of eICIC subframes versus normal MBSFN subframes deteriorates

Engineering Contradiction:
Improveresource utilizationVSAvoidindependent control capability
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent segments MBSFN subframes into two distinct types: eICIC MBSFN subframes and normal MBSFN subframes. This segmentation allows independent control and configuration of each type through separate higher-layer parameters (mbsfn-SubframeConfigList for eICIC and mbsfn-SubframeConfig for normal), resolving the contradiction by enabling both resource utilization and independent control capability simultaneously

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different properties and configurations to different types of MBSFN subframes. eICIC MBSFN subframes have specific characteristics (transmission of CRS only in first OFDM symbol, muted PDSCH) while normal MBSFN subframes have different characteristics (MBMS data transmission). This allows each subframe type to be optimized and controlled independently according to its specific function

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If ABS and MBSFN subframes are used for eICIC to reduce inter-cell interference, then interference reduction is improved, but the complexity of managing and reconfiguring subframe settings deteriorates

Engineering Contradiction:
Improveinter-cell interferenceVSAvoidsubframe setting management
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the subframe configuration into distinct types (eICIC MBSFN subframes and normal MBSFN subframes) with separate configuration parameters. This segmentation simplifies management by providing clear, independent control mechanisms for each type, reducing the complexity of managing and reconfiguring subframes while maintaining interference reduction benefits

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces specific higher-layer parameters (mbsfn-SubframeConfigList, mbsfn-SubframeConfig, subframeAllocation) that allow flexible reconfiguration of MBSFN subframe patterns. These parameter changes enable dynamic adjustment of eICIC subframe settings without affecting normal MBSFN operations, simplifying the management process while maintaining interference coordination effectiveness

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2632197B1Mobile communication method and radio base station
Publication Date: 2020.11.25 NTT DOCOMO INC
  • EP2632197B1 patent drawingFigure 1
  • EP2632197B1 patent drawingFigure 2~3
  • EP2632197B1 patent drawingFigure 4~6

AI summary

A mobile communication method according to the present invention includes a step of setting, by a radio base station eNB#10, when a subframe designated by a pattern of ABS, the pattern being notified by a radio base station eNB#1, matches a subframe set as an MBSFN subframe, the matching subframe as an MBSFN subframe used for "eICIC".